A conventional stereoscopic image display apparatus for displaying a stereoscopic image on a display screen as shown in FIG. 5, uses a pair of image signals generated by two video cameras 32, 33 located at a predetermined distance from an object 31 at with predetermined separation therebetween. The pair of image signals is then displayed on a single display screen 36 by two display devices, such as projectors, 34, 35, respectively, overlapping each other.
However, such conventional stereoscopic image display apparatus have drawbacks in that they require two separate display devices in order that two images, i.e., the left and right image, may be overlappingly displayed on a single display screen. This causes an increase in the size of the stereoscopic image display device and complicates its mechanical structure.
It is desired to provide a stereo projection optical system which can overcome the above-described deficiencies.